I don't mind a QB being mobile - Rodgers, Wilson and Luck typically pick up a couple first downs each game with their legs. But an NFL qb has to be able to make his progressions and see the whole field. The problem with the guys you mentioned is that their first instinct is to tuck the ball and run if their first read isn't there. NFL defenders are too fast for that to be effective.
Agree on Rodgers, Wilson (kind of), and Luck. I don't consider Rodgers and Luck duel threat guys though.